Cloud computing is known which is able to use as many machine resources as necessary, whenever necessary. In cloud computing, resources may be shared among a plurality of persons.
In addition, cloud computing allows an operation form of an individual and automatic operation for each tenant (e.g., a system provided for each cloud user, or the like). For example, a variety of coping methods are preliminarily prepared so that the system is automatically operated, using the prepared coping methods. Here, coping methods, which are, for example, various rules for automatic operation, have described therein what type of countermeasure is supposed to be taken for what type of event such as occurrence of failures or errors.
As a technique of utilizing the result of countermeasure taken for failures, there is, for example, a technique that calculates the effect of trouble shooting as an evaluation value and also allows shared reference between similar devices.
In addition, there is a technique for sorting out effective rules by calculating an application evaluation value of a failure coping rule, and comparing the calculated application evaluation value with an application reference value of a self-failure recovery device.
Furthermore, as a policy refining scheme directed to autonomous operation management, there is a technique for determining whether or not the policy is divertible by determining the similarity of system configurations using a data model for managing the correlation between a policy and a system configuration.
When utilizing the result of countermeasure for a failure or the like, it is also important to correctly determine whether or not a failure has occurred in the system. Accordingly, there is conceived a technique for reducing the burden on the system administrator when providing determination criteria for detecting future failures, for example. In addition, there is also conceived an abnormal condition detecting device capable of predicting a various types of abnormality for which it is not necessarily clear how to identify the cause.    Japanese Laid-Open Patent Publication No. 2010-211597    Japanese Laid-Open Patent Publication No. 2006-53728    Japanese Laid-Open Patent Publication No. 2013-229064    Japanese Laid-Open Patent Publication No. 2013-011987    “Service-oriented policy refinement method on autonomous operation management”, Mitsuhiro OONO, Kiyoshi KATO, Ryuichi HIRAIKE, IEICE (The Institute of Electronics, Information and Communication Engineers) technical report, Jul. 29, 2005, Vol. 105, No. 227, p. 13-18
When preparing a coping method for a particular system, it is efficient to prepare the method referring to the countermeasures that have been actually taken for many other systems. In such a case, it is possible to prepare a coping method which is useful for a particular system by evaluating whether or not each of the countermeasures taken many times in the past is useful for the particular system.
As one criterion for evaluating the countermeasures that have been taken in the past, there may be used a criterion related to the timing at which the countermeasure has been taken. For example, useful countermeasures for serious failures are often taken immediately after the start of operation (release) of the system, and the countermeasure taken most recently is often a useful countermeasure using the latest technology. Accordingly, it is possible to increase the reliability of evaluation by setting higher a value (usefulness) indicating availability of the countermeasure as a difference between the time at which the countermeasure has been taken and the start time of operation or the present time is smaller.
Here, regarding how much difference is provided depending on the difference of time of taking the countermeasure for the system, it is also possible to uniformly determine the difference of usefulness in advance, regardless for which system the countermeasure has been taken. However, such a uniform determination may not be appropriate in some cases.
For example, the period from when operation of a system is started to when the system enters stable operation (rate of maturing) differs between a system the operation of which is started after a sufficient time has been taken for development and testing, and a system the operation of which is started after only a short time has been taken for development and testing. With regard to a countermeasure taken after a predetermined time has elapsed from the start of system operation, therefore, the countermeasure will be taken after the stable operation if the system has quickly matured, but the countermeasure will be taken before the stable operation if the system has gradually matured. The importance of countermeasure is different between a countermeasure taken before the stabile operation and a countermeasure taken after the stable operation, and therefore evaluating the usefulnesses of both the countermeasures equally may deteriorate the reliability of evaluation.